71K5 - BP71K5's Just for fun build

[tRustyK5]

You must have a newer version of the NV4500. Mine is the 14mm thread...and pretty much all the different 5 speed's in the fullsize trucks use the same shifter. The shifter I got was off of a mid 90's half ton with either the Getrag or the NV3500.

The throwout bearing I used was what came with the clutch kit. I ordered the hays "Diesel Super Truck" clutch which is 12.125", and was specific to a 6.2 in a mid 80's truck. To finally get my slave bled I submerged the whole thing in fluid and pushed the rod in and out a few times until I saw no more bubbles. Then with the bleeder port oriented higher than the hose port I cycled pedal a few times. My clutch pedal is great, and this was what worked for me when every other method I tried was not working.

One thing i added was a small return spring to keep the throwout bearing from having a bit of pressure on it at all times. I know they're designed to run against the release fingers, but that just seemed wrong to me.

Oh yeah, the shifter boot is off of an S-10 with 5 speed. Seems to work quite well with the NV4500/Getrag/NV3500 shifter and looks good to me.

Rene

 

[Greg72]

Jeebus......this sure seems like a lot of work.

Not surprising, actually. I only know a handful of folks who have done the NV4500 conversion and they all said the same thing:

"I love it, it's the greatest thing ever.........but, it was a lot more work and a lot more money than I expected. If I had to do it again, I'm not sure I would."

Sounds like your fight is just about over, and there will be nothing left to do but enjoy it.

Maybe you could write up a basic Tech Article on some of the specific issues you had to solve, and provide part numbers and estimated prices for the parts that you had to figure out the hard way???

 

[bp71k5]

So I did some research on bellhousing from AA. I found a very small note in the J**P instruction manual (no, I didn't read the manual first) that says the bellhousings are designed for centerforce clutches which are high profile and that using another clutch type may require a different throwout bearing if using a low profile clutch. I suspect mine is a low profile clutch and hence requires a different bearing.

While it was out, I also took a stab at shortening the fluid line for the clutch. This would allow it to only run downhill instead of the tangled mess it started as. I cut out most of the metal portion and some of the plastic portion and re-welded the fittings back on. I also had to use a heat gun on the plastic hose side of it to straighten out some bends to work better. No idea if the welds will hold, but the pic shows the hose now and it just goes straight down to the slave.

As a backup, I ordered some fittings from AA that adapt this weird GM fitting type to standard brake line threads. This will let me build a proper hose if the welds don't hold on the existing one.

One issue created by the longer bearing is that the slave is much too close to the AA bracket I bought (look in the last picture), which turns out is only designed for 88-91 slaves. (i bought a 92-95 to match the tranny) I had to mod it a bit to get it to work. Although the new fork position means this bracket just won't work at all. So I have a drawing for a new one which should provide more clearance and is a little simpler than the welded up version AA uses. I'm planning to have it laser cut around here locally to give my grinder a break. If anyone wants the drawing for it, let me know.

I do plan on writing up a list of everything I did for someone else doing this. This would have been a ton easier if one existed beforehand.

 

[bp71k5]

So I got the new bracket cut out, fitted it, painted, and installed. This new one is designed for the 92-95 slave cylinder instead of the early style like Advanced Adaptors requires. This new one also fits so much better with the lack of body lift I have and is even more sturdy than the AA version.

For reference, all of the AA conversion stuff uses mid 80's parts for the clutch. I chose the 92-95 clutch master and slave because the master mounts straight on the firewall, and the earlier versions mount at an angle according to Yukon Jack's threads and pictures. I'm not sure yet if this was a good choice, but I seemed to have made it through the issues.

The issue with this later combo is that the fittings are an odd press-in type that don't use theads. I found some fitting for a Jeep from Advance Adaptors that are the same as these GM fittings (see last picture) as well as a steel braided hose that I can use to build a real clutch hose (not like the welded version I hacked up). This is a much cheaper option and is going to be more reliable.

Next step is to build a new slave pushrod and bleed everything again. Once that's done, I can drive it out of the garage. In the downtime waiting on parts, I've also added a later model hi-amp 2-wire alternator and dual electric fans.

For those interested, I did a quick scan of receipts to estimate what all this costs and posted it in my blog. The cost of the tranny itself and the driveshafts are easily the largest items.

 

[BGKYK5]

I am waiting to see how much you love it once it is running (and for the tech article). I would love to go manual and keep overdrive, but with the amount it cost you (gulp!), my 700R4 is looking pretty good! Next time I win the lottery, I'll start hunting for a NV4500.

 

[bp71k5]

I did get it to move about 2 inches backwards by forcing the tranny in gear by accident. It did seems pretty cool.

Depending on your lift and other truck details, it may not cost as much. the tranny is very hard to find on the west coast. It seems they are in wrecking yards all over the midwest (it seems).

The driveshafts are another story. If you already have CV shafts, those are much cheaper to shorten/lengthen. For example, shortening my rear shaft was less than $50. I did save a few bucks by having them re-use some parts from my old front CV shaft.

 

[bp71k5]

Finally got the clutch hooked up. What a pain.

Turns out the master cylinder is actually pointed slightly downward and was causing some air to stay in there when bleeding. I had to remove the entire assembly and bleed it off the truck. It turned out to be much easier that way because I could hear when all the air was out while cycling the pushrods.

I ran into some other issues with the rubber boot to cover the clutch fork (I ended up having to fab one from a hurst shifter rather than use the one from advanced. I also hooked up the rear drive shaft. Angle is a little off but will get me by for a while till I button everything back up.

In any case, as you can see, I pulled it out of the garage!

One thing that kinda scared me into thinking I screwed something up was that I had the doubler in extra-low when I pulled out and didn't realize it. The thing has a ton of torque and was squeeling the tires with just a little bit of gas. I think I'm gonna love this...

 

[tRustyK5]

Sure is a long combo isn't it? I seem to recall 48" from bell to CV on mine.

Rene

 

[bp71k5]

Yea, I keep thinking this would be perfect for a burb.

I also drive it down the street and it shifts rally nice. It's almost like driving a car.

Also while you're here, on my tranny there's a little plastic plug right up on the drivers side of the shift tower. It's just pressed in there. Any idea what that's for? I assume some kind of speed sensor for later model engines (which I don't have) so I've got to plug it up or do something with it. Maybe it's for a reverse sensor?

 

[Yukon Jack]

Congrats on getting the clutch worked out - hydrualic is nice but sure a pain in the rear to get working!

Wild so see such a short rear driveshaft. Looks nearly as short as a front driveshaft

 

[bp71k5]

Actually, you're right. I was able to swap the shafts and the rear fit on the front ok, but was about an inch too short. The front was about an inch too long on the back.

If you think about it, your adding the same amount of length to the front as you are taking from the back. So if both your driveshafts use the same mounts and CV's then it should be a direct swap. Mine was an issue because I added a longer tranny at the same time.

 

[bp71k5]

Final odds and ends followed by a shake down run on the freeway

One of the last issues with the conversion was the clutch fork boot. The version you get from AA of course is meant for a Jeep arm so it doesn't work well. What I ended up doing was cutting all of it off except for the part that fits onto the bellhousing and then riveted on a section from a hurst shifter boot to get one that works quite well.

The bracket I had made up also works perfectly to mount the slave cylinder.

 

[bp71k5]

Then I drove it down to have the mufflers re-installed. The passenger side pipe runs right inside the frame rail. I've been keeping an eye on the fuel line temperature (by hand) and it seems to get warm, but not hot to the touch. I still will likely try to make some kind of shield just in case.

It also doesn't leave a lot of room to put the bracket back on the 205, but I think I can tweak the pipes a bit to get some more room.

 

[bp71k5]

Then I taped the tranny cover back on and also finished up the shift lever. I used the knob from the 5-speed shifter I will be modifying to shift the doubler. It looks kinda lame, but is pretty functional until I find something better.

I just welded a bolt onto the top so the knob could thread right on. The entire shifter is just a metal tube with nuts welded onto each end.

I did take it for a nice drive on the freeway and what a difference there is. I almost have the opposite problem I did before. I have to be going about 70mph before I can shift into 5th or the RPM's are too low. I may have to get better gears.

I have to say driving it is way more fun now! The tranny shifts pretty smooth and the truck is surprisingly easy to drive. It's almost as easy as my vw.

I've just got the doubler in hi gear since there's no where to test it out easily since I can't shift it, but I did try it out for about 20 feet and it's waaaay slow.

Anyway, thanks to everyone for the advice. It helped a lot having this place to ask questions and figure out how to solve the problems i ran into.

Next up is back to my radio, and some attention to the hard top. As you can see it needs some help.

 

[Yukon Jack]

Congrats on getting it out on the open road!!! So are you saving the top or will you try to get one in better shape?

 

[bp71k5]

Yea, I'm going to try and save it. I've already pieced back together the hatch so I'm already committed now.

 

[Jimmy4matt]

I've been following your thread for months because I've wanted to put an nv4500 in my '71 Jimmy. I going to have to wait a while to do it. That looked like a ton of work. I just swapped my 12 bolt for a 14. It had 3.73 gears. I regeared the dana 44. If you want the gears or the 12 bolt and the front gears let me know. Also, there's a shop in Santa Clara that'll install your diff stuff for $175 a pop if you don't have a better deal.

 

[bp71k5]

The hardest part is actually paying for parts. If you have a warm place to work, it's not difficult. If you get around to doing it, drop me a line if you need a hand.

 

[BUDDY]

I'm stoked for ya!! Congrats on getting it driveable again!!

So now that you are trying to "restore" the top, (SHEESH!! at least it's fiberglass), when are you going to get back to the single triple shifter for the t-cases? Huh?!, Huh!?

Also, is it possible that you're front shaft will hit the exhaust pipe when fully compressed on that side?

Do you have the template an/or measurements for the slave bracket?

Good job all around!!

Later,
Buddy

 

[bp71k5]

when are you going to get back to the single triple shifter for the t-cases

I'll be working on it little by little over a while. Now that it's drivable, it's hard to stay away from the other things that need attention. To do it right, I really need to fab up more pieces than I originally thought. Since it's not very expensive to get stuff laser cut, I may design some new shift parts instead of welding and grinding the hurst versions. The parts are pretty simple so it'd be straightforward.

Also, is it possible that you're front shaft will hit the exhaust pipe when fully compressed on that side?

No, it clears ok as the bend is away from the CV joint. I test fit it after taking it to the muffler shop.

Do you have the template an/or measurements for the slave bracket?

Yep, I even have two extras since the cost was the same for under three. Want one? I can also post a drawing of it that anyone can use to fab it up.